Flexible seal for a vapor cavity

ABSTRACT

A seal is disclosed for a tank having a floating roof wherein a mounting member is pivoted on the floating roof and a sealing member is carried by the free end of the mounting member for sealing a vapor cavity between the floating roof and the tank.

United States Patent [191 Nishkian et al.

1451 Apr. 2, 1974 FLEXIBLE SEAL FOR A VAPOR CAVITY [75] Inventors: Martin A. Nishkian, Long Beach;

Wayne E. Nuttall, San Gabriel, both of Calif.

[73] Assignee: United States Steel Corporation [22 Filed: Feb. 14, 1973 [211 Appl. No.: 332,528

Related US. Application Data [62] Division of Ser. No. 134,934, April 19, 1971, which is a division of Ser. No. 879,022, Nov. 24, 1969, Pat

52 U.S.Cl ,.t...,. ,.220/265 51 1m.c| B6511 87/18 [58] Field of Search 220/26 R, 268

[56] References Cited UNITED STATES PATENTS 3,589,549 6/1971 Heisterberg 220/26 S 3,434,6l9 3/1969 Nelson 220/26 5 3,724,704 3/1973 Edwards et al. 220/26 R Primary Examiner-George E. Lowrance Assistant ExaminerSteven M. Pollard Attorney, Agent, or Firm-Robert J. Leek, Jr.

[57] ABSTRACT A seal is disclosed for a tank having a floating roof wherein a mounting member is pivoted on the floating roof and a sealing member is carried by the free end of the mounting member for sealing a vapor cavity between the floating roof and the tank.

PATENTEDAPR 2 I974 3,800,975

' sum 2 or a PATENTEDAPR 2 I974 SHEET h [if 8 Fla ,7

SHEET 7 [1F 8 IIMENI'EIIAPR 2f. mm

FLEXIBLE SEAL FOR A VAPOR CAVITY This application is a divisional of US. Pat. application Ser. No. l34,934, filed Apr. 19, 1971, by applicants,'now US. Pat. No. 3,735,891, which in turn was a divisional application of US. Pat. application Ser.

No. 879,022, filed Nov. 24, 1969, now US. Pat. No.

3,618,813, all of said applications and patents being assigned to the assignee of the present application.

BACKGROUND OF THE INVENTION For economic and air pollution reasons the storage of volatile liquids requires a tank that will minimize breathing losses. An effective tank design for this purpose is a tank of the floating-roof type. This design consists of an essentially cylindrical tank fitted with an internal buoyant roof that floats on the surface of the stored product, with a sealing device within the annular space between the floating roof and the tank wall, thus minimizing the vapor lost due to evaporation.

The efliciency'of this type of tank depends on the tightness of the roof-to-tank seal. This seal has been accomplished in the past using metal shoes attached to the roof and sliding on the inside of the tank wall..The shoe is connected to the roof with a flexible curtain. The rigidity of the metal shoes, however, prevents a tight seal because of the tank shell curvature and irregularit'ies in the tank shell.

Other types of seals have been devised in which a flexible membrane is filled with either a liquid, granular material, or other compressiblematerial. This seal is attached to the roof and deviations in the tank shell .contour are overcome by the flexibility of the seal.

OBJECTS OF THE INVENTION It is the general object of this invention to avoid and overcome the foregoing and other difi'iculties of and objections to prior art practices by the provision of a flexible seal between a tank shell and a floating roof which:

a. has its wear cover integrally bonded to the core or filler material to prevent bunch-up or wrinkling of the cover,

b. has a wear cover which is readily reapplied or repaired, c. is reversiblewhen the wear on one side of the wear cover is excessive,

d. has a uniform pressure exerted on the seal,

e. compensates for any out-of-round condition in the tank shell,

f. adjusts for any variation in dimension between the tank shell and the floating roof,

g. provides avapor tight seal between the tank shell and the floating roof, and

h. can be repaired or maintained without draining and cleaning the tank.

BRIEF SUMMARY OF TI-IE INVENTION The aforesaid objects of this invention, and other objects which will become apparent as the description proceeds, are achieved by providing a flexible seal having a mounting member pivoted on the floating roof and a sealing member carried by the free end of the mounting member for sealing the vapor cavity. The sealing member has a rigid core member, a flexible core member surrounding the rigid core member, a wear cover member disposed about the flexible core member, and a support member extending through the sealing member and secured to the rigid core member and to the wear cover member.

In addition, a rectangular self-energizing seal is provided having a sealing member provided with a rigid inner core member; a flexible inner core member disposed about the rigid inner core member; a rigid outer core member disposed about the flexible inner core member; rigid end section members covering the rigid outer core member, the flexible inner core member, and the rigid inner core member; a flexible outer core member disposed about the rigid outer core member, and the rigid end section members; a wear cover member covering the flexible outer member and the rigid end section members; a support rod extending through the sealing member and secured to the rigid end section members; and a pair of generally diagonally disposed scuff pads projecting from the wear cover member, and generally diagonally disposed sealing surfaces on the outer flexible layer. A mounting rod is pivoted on the floating roof and pivotably connected to one of the scuff pads. A counterweight rod is pivotable on the other scuff pad, and counterweight means is carried by the counterweight rod to force the sealing surfaces into sealing engagement with the tank shell and the floating roof.

Also, a flexible substantially square seal is provided having a mounting member pivoted on the floating roof and depending into the vapor cavity, and a sealing member connected to the mounting member and having a flexible inner core member, a rigid, inner core member disposed about the flexible inner core member; rigid end section members covering the rigid inner core member and the flexible inner core member; a flexible outer core member adjacent the rigid end section members and the rigid inner core member; a scuff pad surrounding the rigid end section members and the flexible outer core member; and a support rod extending through the sealing member and connected to the rigid end section members and to the mounting member. The scuff pad and the flexible outer core membe are deformable to seal the vapor cavity.

In addition, a rotary circular seal is provided having a mounting member pivoted at one end of the floating roof, an annular member carried by the other end of the mounting member and rotatable in the mounting member, and a sealing member on the annular member and having a rigid inner core member disposed about the annular member; a flexible outer core member surrounding the rigid inner core member, and a scuff pad about the flexible outer core member.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS For a better understanding of this invention reference should be had to the accompanying drawings, wherein like numerals of reference indicate similar parts throughout the several views and wherein:

FIG. 1 is a fragmentary sectional view of a selfenergizing seal between a tank shell and a floating roof;

FIG. 2 is a view similar to FIG. 1 of an alternative reversible. seal;

FIG. 3 is a side elevational view of a hooked pin for anchoring one end of the seal shown in FIG. 2;

FIG. 4 is a view similar to FIG. 3 of a key bolt for anchoringone end of the seal shown in FIG. 2;

FIG. 5 is a view similar to FIG. 1 of an alternative seal, in its minimum spacing position;

FIG. 6 is a cross sectional view of the sealing member shown in FIG. 5 taken along the line 6-6 of FIG. 7 in the direction of the arrows;

FIG. 7 is a longitudinal sectional view of the sealing member taken along the line 7-7 of FIG. 6 in the direction of the arrows;

FIGS. 8A-8C are fragmentary sectional views of various forms of sectional joints between adjacent sections of the sealing member;

FIG. 9 is a view similar to FIG. 5 showing the sealing member in its maximum sealing position;

FIG. 10 is a view similar to FIG. 5 of an alternative rectangular seal in its minimum spacing position;

FIG. 11 is an enlarged vertical sectional view of the sealing member shown in FIG. 10;

FIG. 12 is a vertical sectional .view of the sealing member taken along the line 12-12 of FIG. 11 in the direction of the arrows;

FIG. 13 is a view similar to FIG. 10 showing the seal in its maximum spacing position;

1 FIG. 14 is aview similar to FIG. 10 of an alternative square seal in its minimum spacing position;

.FIG. 15 is an enlarged sectional view of the sealing member shown in FIG. 14;

' FIG. 16 is a vertical sectional view of the sealing membertaken along the line 16l6 of FIG. 15 in the direction of thearrows;

FIG. 17 is a view similar to FIG. 14 of the seal in its maximum spacing position; i

as manufactured by Goodyear Rubber Co., San Francisco, California.

A flexible wear cover member 20, suitably neoprene or the like, is mounted on the floating roof 12 at one end by a contact bar 20a, bolt 20b and nut 20c, at the other end by a contact angle 20d, contact bar 20a, bolt 20b and nut 20c.

Counterweight means, such as a counterweight 22, is carried by one of the movable links 16a, 16b, 160, (in this case movable link 16d) to force the contact member 18 into contact with the wear cover member 20 so that the wear cover member 20 seals the vapor cavity at S.

The contact member 18 may be semi-circular, as shown in FIG. 1, triangular, semi-hexagonal or the like in cross section.

ALTERNATIVE EMBODIMENTS It will be understood by those skilled in the art that alternatively as shown in FIG. 2 the flexible reversible seal 14 has a support member 24 secured at one end,

' the top end as viewed in FIG. 2, to the floating roof 12 FIG. 18 is a view similar to FIG. 14 of an alternative larly adapted for use in conjunction with a flexible seal between a tank shell and a floating roof, and hence it has been so illustrated and will be so described.

DETAILED DESCRIPTION With specific reference to the form of this invention illustrated in the drawings, and referring particularly to FIG. 1, a self-energizing flexible seal for a vapor cavity 10 between a tank shell 11 and floating roof 12 is indicated generally by the reference numeral 14.

This self-energizing seal 14 has a plurality of spaced quadrilateral type linkage 16, mounted (as by welding) by means of a fixed link 16a to the floating roof l2 and, in addition to the fixed link 16a, has movable links 16b, 16c, 16d pivoted at 16e, 16f, 16g, 16h. A contact member 18 is mounted by means of its mounting plate 18a to one of the movable links 16b, 16c, 16d (in this case the movable link 16c) and also has a cover member 18b, suitably neoprene or the like and a flexible core member 18c, suitably urethane orthe like, between the cover member 18b and ,the mounting plate 18a. The cover member 18b is bonded tothe mounting platel8a at its edges by an adhesive, suitably Type AC Cement by a bolt 20b and nut 200. In the seall4 a tubular sealing member 26 of the seal 14 has a wear cover member 26a, suitably two hemicylindrical sheets, for example neoprene, urethane or the like, vulcanized on both sides, and provided with flanges 26b, 26c and a flexible core member 26d,'suitably urethane or the like. This sealing member 26 has one set of flanges (i.e., flanges 26b) secured, as by contact plates 28a, bolt 28b and nut 280 to the free end of the support member 24 and the other set of flanges (i.e., flanges 260) secured by angle 28d, contact plates 28a, bolt 28b and nut 28c to the other end (i.e., lower end, FIG. 2) of the floating roof 12.

The reversible sealing member 26 seals the vapor cavity 10. Alternatively, as shown in FIGS. 3 and 4, the bolts 28b aridnuts 28c may be replaced by a hooked pin 28:: or the key bolt 28f.

Referring to the round flexible seal 14 shown in FIGS. 5-9, such seal 14 has a mounting member 30 (FIGS. 5,9) pivoted a t'31 on a lug 32 extending from the floating roof 12. A sealing member 33 (FIGS. 5,7) is carried by the free end of the support member 30 (as hereinafter described), for sealing the vapor cavity 10. This sealing member 33 has a rigid core member 34a, 34b (FIGS. 7,8A-8C), suitably polyurethane or the like; a flexible core member, suitably two concentric flexible cores 35a, 35b (FIGS. 5,6,7,8A-8C,9) of urethane foam or the like, surrounding the rigid core members 34a,34b; a wear cover member 36 (FIGS. 5,6,7,8A 8C,9), suitably a replaceable spray coat of dense urethane; and a threaded support member 37 (FIGS. 5,6,7,9) extending through the sealing member 33 and secured by nuts 38 and washers 39 to the wear cover member 36 and to the rigid core member 340. A coupling 39a (FIGS. 5,9) connects the support member 37 to the mounting member 30. v

-The seal 14 has the sectioned rigid core members 34a, 34b (FIG. 7) connected together by a core tube connector 40, suitably polyurethane or the like, secured thereto by an adhesive'such as one of the following:

Trade Mark or Trade Name Manufacturer E. I. du Pont de Ncmours & Co. Union Carbide Corporation Surlyn A ionomcr resin 3M Company B. F. Goodrich Industrial Products Company United States Steel Corporation USS Ncxus" POE-l polymeric material In addition, the sealing member 33 is sectioned into sections S1, S2 (FIGS. 7,8A-8C) which sections S1,S2 are connected together by a boot 41, suitably of dense urethane or the like, with (FIG. 8B) or without (FIG. 8A) one of the above adhesives. The joints between sections S1, S2 may have one section S1 (FIG. 8A) provided with a tongue and groove 42 or both sections S1, S2 (FIGS-8B, 8C) provided with tongue and groove 42. In FIG. 8C the registering tongue and grooves 42 are cemented together with one of the above adhesives.

As shown in FIGS. 5,9 the seal 14 is provided with a flexible weather shield 43, suitably neoprene, urethane elastomer or the like, secured to the floating roof 12 at 44 and to the tankwall 11 at 45 and supported by a plurality of support rods 46 extending from anchor 45 to pivot 31. The seal 14 moves from the minimum spacing position (FIGQS) to the maximum spacing position (FIG. 9).

The seal 14 shown in FIGS. l0 -l3 has a mounting member 47 (FIGS. 10,13) pivoted at 48 on a bracket 49 projecting from the top of the floating roof 12 and extends arcuately downwardly into the vapor cavity 10. The seal 14 also has a sealing member 50 (FIGS. 10,11,13) having a rigid inner core member 51 (FIG. 11, suitably polyurethane foam or the like); an inner flexible core member 52, suitably urethane elastomer or the like disposed about the rigid inner core member 51, an outer rigid core member 53, suitably polyurethane foam or the like, disposed about the flexible inner core member 52; rigid end section members 54, suitably polyurethane foam or the like, and covering the outer rigid core member 53, the flexible inner core member 52 and the rigid inner core member 51; a flexible outer core member 55, suitably an 0 type elastomer of the type 2069 manufactured by CPR Division of Upjohn Co. or the like, covering the outer rigid core member 53 and the end section members 54; a wear cover member 56, suitably urethane elastomer or the like, covering the flexible outer core member 55 and the rigid end section members 54; a support rod 57 (FIGS. 10-13) extending through the rigid end sections 54 and rigid inner core member 51 of the sealing member 50 and secured to the rigid end section member 54 by nuts 58 and washers 59; a pair of generally diagonally disposed scuff pads 60, suitably dense urethane or the like, (FIGS. 10,11,13) projecting from the wear cover member 56; and generally diagonally disposed sealing surfaces 61 (FIGS. l1, 13) on the flexible outer core member 55. e

The mounting rod 47 is pivoted at 62 on the left hand scuff pad 60 (as viewed in FIGS. 10,13). A counterweight rod 63 (FIGS. 10,13) is pivoted at 64 on the right hand scuff pad 60 (FIGS. 10,13) and carries a counterweight 65 (FIGS. 10,13) for moving the sealing member 50 into the minimum space sealing position shown in FIG. 10 and the maximum space sealing position shown in FIG. 13 where the sealing surfaces 61 seal against the tank wall 11 and floating roof 12.

As shown in FIGS. 11,12 the rigid outer core member 53 has a pair of rigid outer cores 53a,53b, each of which is step-buttlaminated. The butted sections are secured together with or without one of the following adhesives:

Trade Mark or Trade Name Manufacturer E. l. du Pont de Nemours & Co. Union Carbide Corporation Surlyn A ionomer resin 3M Company B. F. Goodrich Industrial Products Company United States Steel Corporation USS Nexus PQE-I polymeric material In addition, the rigid end section core member 54 has a pair of end sections 54a, 54b with a washer 59 and a nut 58 disposed therebetween. As shown in FIG. 11, the rigid inner core member 51 is also sectioned and held together with or without one of the above mentioned adhesives. Referring to FIG. 12 it will be noted that the sealing member 50 is also sectioned at S1, S2, the sections S1, S2 being connected together by a connector boot 65, suitably polyurethane or the like. One of the above mentioned adhesives may be used to secure the boot 65' to wear cover members 56.

As shown in FIGS. 10,13 a weather shield 66, suitably of neoprene, urethane elastomer or the like, extends from pivot 67 on the tank wall 11 to securement point 68 on the floating roof 12 and is supported by a plurality of telescoping rods 69 extending between the pivot 67 on the tank wall 11 to the pivot 48 on the lug 49 on the floating roof 12. The weather shield 66 covers the vapor cavity 10.

The flexible substantially square seal 14 shown in FIGS. 1417, has a plurality of spaced mounting members 70 (FIGS. 14,17) each pivoted at 71 on a bracket 72 extending from the top of the floating roof 12. This member 70 extends into the vapor cavity 10 and is threadably connected at 73 to a support rod 74 extending through a sealing member 75.

The sealing member 75 has a flexible inner core member 76 (FIG. 15), suitably urethane or the like, disposed about the support rod 74; a rigid inner core member 77, suitably polyurethane or the like, disposed about the flexible inner core member 76, rigid end section members 78, suitably urethane elastomer or the like covering the flexible inner core member 76 and rigid inner core member 77; a flexible outer core member 79, suitably urethane or the like and of triangular cross section or the like, adjacent the rigid inner core member 77 and rigid end section members 78; and a scufi' pad 80, suitably polyurethane foam or the like, covering the flexible outer core members 79 and rigid end section members 78.

The support rod 74 is connected to the rigid end section members 78, as by nuts 81 and washers 82.

In FIG. 15 the rigid end section members 78 each have at least two rigid end sections 78a,78b. The seal- Trade Mark or Trade Name Manufacturer Sur lyn" A ionomer resin E. I. du Pont de Nemours &

Bakelite" phenoxy rcsins PKHH AN D Union Carbide Corporation PAHJ Scotch-Hold" brand structural 3M Company adhesives A-l 103-8 adhesives B. F. Goodrich Industrial Products Company USS "Nexus" POE-I polymeric material In addition, a weather shield 84 (FIGS. 14,17), suitably neoprene, urethane elastomer or the like, extends from a pivot 85 on a lug 86projecting from tank ,wall 11 to a securement point 87 on the floating roof l2 and is supported by a plurality of rods 88 each extending between pivot point 85 on lug 86 to pivot point -71 on bracket 72. 1

The rotary generally circular seal 14, shown in FIGS. 18,19 has mounting members 89, each pivoted at 90 on a bracket 91 projecting from the top, as viewed in FIG.- 18, of the floating roof 12. An annular metal member-92 is carried by the other ends (i.e., the depending ends, as viewed in FIG. 18) of the mounting members 89 in suitable holes 93 therein, and is rotatable in such holes 93. A sealing member 94 has a rigid inner core member 95, suitably polyurethane or the like, surrounding the annular member 92; a flexible outer core member 96, suitablyurethane or the like, disposed about the rigid inner core member 95; and a scuff pad 97, suitably polyurethane or the like, surrounding the flexible outer core member 96.

As shown in FIG. 18, the flexible outer core member 96 has at least two flexible Outer cores 96a,96b. The mounting member 89 extends into the vapor cavity so that the annular member 92 is closer to the tank shell 11 than to the floating roof 12 (cd,,cdthereby compressing the sealing surface of the scuff pad 97 adjacent the tank shell 11 more than the sealing surface of the scuff pad 97 adjacent-the floating roof 12.

SUMMARY OF THE ACHIEVEMENTS OF THE OBJECTS OF THE INVENTION It will be recognized by those skilled in the art that the objects of this invention have been achieved by providing a flexible seal 14 (FIG. 1 l4 (FIGS. 24), etc., between a tank shell ll and a floating roof 12, which seal has its wear cover integrally bonded to the core or filler material to preventbunch-up or wrinkling of the cover; has a wear cover which is readily reapplied or repaired, is reversible when the wear on one side of the wear cover is excessive; has a uniform pressure exerted on the seal; compensates for any out-of-round condition in the tank shell; adjusts for any variation in dimension between the tank shell and the floating roof; provides a vapor tight seal between the tank shell and the floating roof; and can be repaired or maintained without draining and cleaning the tank.

While in accordance with the patent statutes preferred and alternative embodiments of this invention have been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

We claim: 1. A seal for a vapor cavity between a tank shell and a floating roof, said seal having:

a. a mounting member pivoted on said floating roof,

b. a sealing member carried by the free end of said mounting member, for sealing said vapor cavity, 1. said sealing member having a rigid core member, a flexible core member surrounding said rigid core member, a wear cover member disposed about said flexible core member, and a support member extending through said sealing member and secured to said rigid core member and to said wear cover member.

2. The seal'recited in claim 1 wherein said sealing member is sectioned, said sections being connected together by a boot member.

3. The seal recited in claim 2 wherein one of said sections has a tongue and groove.

4. The seal recited in claim 1 wherein sections have a tongue and groove. 7

5. The seal recited in claim 4 wherein said sections are adhesively secured together.

6. The seal recited in claim 2 wherein said sealing member is adhesively secured to said sections.

7. The seal recited in claim 1 wherein said rigid core member is sectioned, saidsections being connected by core tube connectors.

8. The seal recited in'claim 1 wherein said flexible core member has a pair of concentric flexible cores.

9. The seal recited in claim 1 and having a flexible weather shield.

10. A rectangular self-energizing seal for a vapor cavity between a tank shell and a floating roof, said seal having: Y

a. a sealing member having arigid inner core member, a flexible inner core member disposed about said rigid inner core member; a rigid outer core member disposed about said flexible inner core member; rigid end section members covering said both of said rigid outer core member, said flexible inner core member, and said rigid inner core member, flexible outer core member disposed about said rigid outer core member, and said rigid end sections members; a wear cover member covering said flexible outer member and said rigid end section members; a support rod extending through said sealing member and secured to said rigid end section members, a pair of generally diagonally disposed scuff pads projecting from said wear cover member, and generally diagonally disposed sealing surfaces on said outer flexible layer,

b. a mounting rod pivoted on said floating roof and pivotably connected to one of said scuff pads, c. a counterweight rod pivotable on the other scuff pad, and d. counterweight means carried by said counterweight rod to force said sealing surfaces into sealing engagement with said tank shell and said floating roof. 11. The seal recited in claim 10 wherein said rigid outer core member has at least two rigid outer cores.

12. The seal recited in claim 10 wherein said rigid end section members have at least two end sections.

13. The seal recited in claim wherein said rigid inner core member is sectioned.

14. The seal recited in claim 10 wherein said rigid outer core member is stepsectioned.

15. The seal recited in claim 10 wherein said sealing member is sectioned.

16. The seal recited in claim and having a connector boot for joining adjacent sections.

17. The seal recited in claim 10 and having a weather shield above said sealing member for covering said vapor cavity.

18. A flexible substantially square seal for a vapor cavity between a tank shell and a floating roof, said seal having:

a. a mounting member pivoted on said floating roof and extending into said vapor cavity,

b. a sealing member connected to said mounting member and having a flexible inner core member, a rigid inner core member disposed about said flexiblev inner core member, rigid end section members covering said rigid inner core member and said flexible inner core member, a flexible outer core member adjacent said rigid end section members and said rigid inner core member, a scuff pad surrounding said rigid end section members and said flexible outer core member, a support rod extending through said sealing member and connected to said rigid end section members and to said mounting member,

1. said scuff pad and said flexible outer core member being deformable to seal said vapor cavity. 19. The seal recited in claim 18 wherein said rigid end section members each have at least two rigid end sections.

20. The seal recited in claim 18 wherein said sealing member is sectioned. v

21. The seal recited in claim 20 and having a connector boot for joining adjacent sections of said sealing member.

22. The seal recited in claim 18 and having a weather shield to protect said vapor cavity mounted between said tank shell and said floating roof.

23. A rotary circular seal for a vapor cavity between a tank shell and a floating roof, said seal having:

a. a mounting member pivoted at one end on said floating roof,

b. an annular member carried by the other end of said 'mounting member and rotatable in said mounting member, and

c. a sealing member on said annular member and having a rigid inner core member disposed about said annular member, a flexible outer core member surrounding said rigid inner core member, and a scuff pad about said flexible outer core member.

.24. The seal recited in claim 23 wherein said flexible outer core member has at least two outer flexible cores.

25. The seal recited in claim 23 wherein said mounting member depends into said vapor cavity so that the compression on the side of said scuff pad adjacent-said tank shell is greater than the compression on the other side of said scuff pad adjacent said floating roof. 

1. A seal for a vapor cavity between a tank shell and a floating roof, said seal having: a. a mounting member pivoted on said floating roof, b. a sealing member carried by the free end of said mounting member, for sealing said vapor cavity,
 1. said sealing member having a rigid core member, a flexible core member surrounding said rigid core member, a wear cover member disposed about said flexible core member, and a support member extending through said sealing member and secured to said rigid core member and to said wear cover member.
 2. The seal recited in claim 1 wherein said sealing member is sectioned, said sections being connected together by a boot member.
 3. The seal recited in claim 2 wherein one of said sections has a tongue and groove.
 4. The seal recited in claim 1 wherein both of said sections have a tongue and groove.
 5. The seal recited in claim 4 wherein said sections are adhesively secured together.
 6. The seal recited in claim 2 wherein said sealing member is adhesively secured to said sections.
 7. The seal recited in claim 1 wherein said rigid core member is sectioned, said sections being connected by core tube connectors.
 8. The seal recited in claim 1 wherein said flexible core member has a pair of concentric flexible cores.
 9. The seal recited in claim 1 and having a flexible weather shield.
 10. A rectangular self-energizing seal for a vapor cavity between a tank shell and a floating roof, said seal having: a. a sealing member having a rigid inner core member, a flexible inner core member disposed about said rigid inner core member; a rigid outer core member disposed about said flexible inner core member; rigid end section members covering said rigid outer core member, said flexible inner core member, and said rigid inner core member, flexible outer core member disposed about said rigid outer core member, and said rigid end sections members; a wear cover member covering said flexible outer member and said rigid end section members; a support rod extending through said sealing member and secured to said rigid end section members, a pair of generally diagonally disposed scuff pads projecting from said wear cover member, and generally diagonally disposed sealing surfaces on said outer flexible layer, b. a mounting rod pivoted on said floating roof and pivotably connected to one of said scuff pads, c. a counterweight rod pivotable on the other scuff pad, and d. counterweight means carried by said counterweight rod to force said sealing surfaces into sealing engagement with said tank shell and said floating roof.
 11. The seal recited in claim 10 wherein said rigid outer core member has at least two rigid outer cores.
 12. The seal recited in claim 10 wherein said rigid end section members have at least two end sections.
 13. The seal recited in claim 10 wherein said rigid inner core member is sectioned.
 14. The seal recited in claim 10 wherein said rigid outer core member is step sectioned.
 15. The seal recited in claim 10 wherein said sealing member is sectioned.
 16. The seal recited in claim 15 and having a connector boot for joining adjacent sections.
 17. The seal recited in claim 10 and having a weather shield above said sealing member for covering said vapor cavity.
 18. A flexible substantially square seal for a vapor cavity between a tank shell and a floating roof, said seal having: a. a mounting member pivoted on said floating roof and extending into said vapor cavity, b. a sealing member connected to said mounting member and having a flexible inner core member, a rigid inner core member disposed about said flexible inner core member, rigid end section members covering said rigid inner core member and said flexible inner core member, a flexible outer core member adjacent said rigid end section members and said rigid inner core member, a scuff pad surrounding said rigid end section members and said flexible outer core member, a support rod extending through said sealing member and connected to said rigid end Section members and to said mounting member,
 19. The seal recited in claim 18 wherein said rigid end section members each have at least two rigid end sections.
 20. The seal recited in claim 18 wherein said sealing member is sectioned.
 21. The seal recited in claim 20 and having a connector boot for joining adjacent sections of said sealing member.
 22. The seal recited in claim 18 and having a weather shield to protect said vapor cavity mounted between said tank shell and said floating roof.
 23. A rotary circular seal for a vapor cavity between a tank shell and a floating roof, said seal having: a. a mounting member pivoted at one end on said floating roof, b. an annular member carried by the other end of said mounting member and rotatable in said mounting member, and c. a sealing member on said annular member and having a rigid inner core member disposed about said annular member, a flexible outer core member surrounding said rigid inner core member, and a scuff pad about said flexible outer core member.
 24. The seal recited in claim 23 wherein said flexible outer core member has at least two outer flexible cores.
 25. The seal recited in claim 23 wherein said mounting member depends into said vapor cavity so that the compression on the side of said scuff pad adjacent said tank shell is greater than the compression on the other side of said scuff pad adjacent said floating roof. 